Iliacus (left) (Musculus iliacus)
Educational content only — not medical advice.
Anatomy
Fills the iliac fossa and joins psoas major to form iliopsoas — the body’s strongest hip flexor; the femoral nerve passes between the two muscles into the thigh.
Origin & insertion
Upper two-thirds of the iliac fossa and the inner pelvic brim fascia.
Action
Powerfully flexes the thigh at the hip; with the thigh fixed it tilts the pelvis forward — the core of every step and trunk lean.
Innervation
Femoral nerve (L2–L3).
Clinical notes
Chronic weakness converts hip gait into a shuffling pattern; an iliac abscess beneath its fascia is palpable only deep in the fossa and hides on exam — the classic positive psoas sign.
Related structures
Educational references
FAQ
What is the role of the Iliacus (left)?
Fills the iliac fossa and joins psoas major to form iliopsoas — the body’s strongest hip flexor; the femoral nerve passes between the two muscles into the thigh.
Why is the Iliacus (left) clinically important?
Chronic weakness converts hip gait into a shuffling pattern; an iliac abscess beneath its fascia is palpable only deep in the fossa and hides on exam — the classic positive psoas sign.
Source & license
BodyParts3D, © The Database Center for Life Science licensed under CC Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/). license details